Illumination device

ABSTRACT

A darkfield type illumination device for performing slide agglutination tests or the like. The device comprises a casing having an opening therein. A transparent slide having a reaction area thereon is mounted on the casing with the reaction area positioned over the opening. A nonreflective surface is provided in the casing below the opening. Illumination from the light source is transmitted in two paths extending from opposite sides of and below said opening upwardly at an angle to the opening. Such angle is between about 30* and 35* to provide the maximum benefit of particle illumination of material in the reaction area of the slide and darkfield effect of the device. Preferably the two paths of illumination pass through only corresponding onehalf sections of the reaction area of the slide to provide enhanced illumination of the particles.

United States Patent 1 Miller [54] ILLUMINATION DEVICE [75] Inventor: Curtis E. Miller, Fullerton, Calif.

[73] Assignee: Beckman Instruments, Inc., Fullerton, Calif.

[22] Filed: May 15, 1972 [21] Appl. No.: 253,523

[52] U.S. C1 ..240/2.18, 350/89 [51] Int. Cl ..F21l 1/00 [58] Field of Search ..240/1 EL, 2 R, 2 AT, 240/2 MA, 2.18, 8.14, 8.16; 40/106.1; 128/2 G', 2 L; 355/67, 70; 350/87, 89

[56] References Cited UNITED STATES PATENTS 1,461,367 7/1923 Ott et a1. ..240/2 MA X 2,332,668 10/1943 Richards ..350/89 1,951,636 3/1934' Straubel ..240/2 MA X 2,807,187 9/1957 Petty ..240/2.18 3,352,277 11/1967 Schmidt ..240/1 EL X Primary ExaminerSamuel S. Matthews Assistant Examiner-Fred L. Braun A ttorney-Thomas L. Peterson and Robert J. Steinmeyer [57] ABSTRACT A darkfield type illumination device for performing slide agglutination tests or the like. The device comprises a casing having an opening therein. A transparent slide having a reaction area thereon is mounted on the casing with the reaction area positioned over the opening. A nonreflective surface is provided in the casing below the opening. Illumination from the light source is transmitted in two paths extending from opposite sides of and below said opening upwardly at an angle to the opening. Such angle is between about 30 and 35 to provide the maximum benefit of particle illumination of material in the reaction area of the slide and darkfield effect of the device. Preferably the two paths of illumination pass through only corresponding one-half sections of the reaction area of the slide to provide enhanced illumination of the particles.

7 Claims, 2 Drawing Figures PATENTEUJUH 51915 ILLUMINATION DEVICE CROSS-REFERENCE TO RELATED APPLICATION This application describes a device which constitutes an improvement upon the illumination apparatus described and claimed in my copending application Ser. No. ll2,976, filed Feb. 5, 1971, now US. Pat. No. 3,692,997, assigned to the assignee of the present application.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates generally to an illumination device and, more particularly, to a device for illuminating a material on a transparent slide such as is used in slide agglutination tests.

2. Description of the Prior Art Slide agglutination tests are employed in medical laboratories for the purpose of ascertaining the type of a persons blood. This is important in cases of blood transfusion where care is to be taken that the blood of the donor be 'of the type compatible with the blood of the patient who is to receive said blood while otherwise the transfusion might result in an unfavorable reaction or even death of the patient.

At the present time, such agglutination tests are being performed by placing slides carrying the bloodblood typing serum mixture upon a frosted glass of a box-like viewer from which light is directed through the frosted glass against the slide and the contents thereof. The test is also sometimes performed by holding the slide over a regular incandescent light in such a manner that some of the rays of the light pass obliquely through the bottom of the slide. Still another method uses an opaque slide, such as a plastic coated cardboard, which is illuminated from above by a regular incandescent light. All these methods suffer from the factthat the type of lighting does not provide good contrast between the agglutinated particles on the slide and the background material thereby making reading of weak agglutinations difficult.

SUMMARY OF THE INVENTION The principal object of the present invention is to provide an improved illumination device for performing slide agglutination tests or the like.

Another object of the invention is to provide a darkfield type device for illuminating agglutination reactions which allows the reactions to be easily read with the naked eye.

According to the principal aspect of the present invention, there is provided a darkfield type illumination device for performing slide agglutination tests or the like. The device comprises a casing having an opening therein. A transparent slide having a reaction area thereon is mounted on the casing with the reaction area positioned over the opening. A nonreflective surface is provided in the casing below the opening. Illumination from the light source is transmitted to two paths extending from opposite sides of and below said opening upwardly at an angle to the opening. I have discovered that by making such angle between about 30 to 35 with respect to the horizontal plane, maximum benefit of particle illumination of material in the reaction area of the slide and darkfield effect of the device is obtained. Preferably the two paths of illumination pass through only corresponding one-half sections of the reaction area of the slide to provide enhanced illumination of the particles.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is an isometric view of the combination illumination device and agglutination slide of the present invention with a portion of the illumination device broken away to show its interior structure; and

FIG. 2 is a transverse vertical sectional view taken along line 2-2 of FIG. 1 with the reaction slide positioned on the illumination device.

DESCRIPTION OF THE PREFERRED EMBODIMENT terial 20 which is subject to an agglutination reaction.

The device 12 is designed to provide a darkfield type of illumination so that agglutination reactions occurring in the wells of the slide 10 may be accurately and easily seen by the naked eye.

More specifically, the device 12 includes an elongated casing 22"including an upper part 24 and lower part 26. A rectangular recess 28 is formed in the upper surface of the casing 22 and extends to the one end 30 of the casing. The recess is dimensioned to receive therein the rectangular slide 10. A indentation 32 is formed in the end 30 to facilitate removal of the slide 10 from the recess 28. A series of cylindrical openings 34 are formed in the recessed portion of the upper part 24 of the casing. The openings 34 are equal in number to the wells 14 in the slide 10 and are in registry therewith when the slide 10 is positioned in the recess. As best seen in FIG. 2, the diameter of the openings 34 is slightly greater than that of the cylindrical wall 16 of the wells 14 so that the wells can fit within the openings 34. It will be of course understood that any number of wells 14 and openings 34 may be provided depending upon the types or number of agglutination tests which are desired to be simultaneously conducted.

As best seen in FIG. 1, the lower part 26 of the casing is formed with a narrow groove 36 which extends about its entire upper perimeter. A lip 38 provided about the lower perimeter of the upper part 24 of the casing is configured to fit within the groove 36 so that the upper and lower parts 24 and 26, respectively, of the casing may be frictionally held together. Longitudinally extending channels 40 are formed in opposite sides of the lower part 26 of the casing. Each channel 40 terminates in a wall 42 spaced from the adjacent end 44 of the part 26. Sheets of reflective material 46 are positioned on opposite sides of the channels 40. A series of light bulbs 48 are positioned in the channels 40, there being provided a pair of light bulbs on opposite sides of and in alignment with each opening 34 in the casing. A pair of elongated conductors 50 extend above and below the bulbs in the channels 40 and the filaments for each bulb are connected to these conductors. The conductors 50 are connected to the wires, not shown, of a cord 52 which terminates in a plug 54 that is adapted to be connected into a conventional household electrical outlet for supplying electrical current to the bulbs 48 to energize the same.

As seen in FIG. 2, the lower part 26 of the casing is formed with oppositely inclined surfaces 56 which extend from the inner surfaces of the grooves 40 upwardly to an upper flat surface 58 which extends longitudinally below all the openings 34 in the upper part 24 of the casing. The surface 58 is nonrefiective so as to provide a darkfield background below the wells 14 in the slide 10. The nonreflective surface may be provided by forming the part 26 from an opaque, preferably black, plastic. Alternatively, the part could be formed of a transparent or reflective material and coated on its surface with a suitable nonreflective layer. In addition, preferably the upper part 24 of the casing 52 is formed of an opaque black plastic to minimize stray reflections of light from the bulbs 48. The lower portion of the upper part 24 of the casing is formed with oppositely inclined surfaces 60 which extend downwardly from adjacent the edges of the openings 34 to near the lips 38 on the bottom portion of the part. As seen in FIG. 2, the surfaces 60 are parallel to the inclined surfaces 56 on the lower part 26 and are spaced therefrom to provide two paths which extend from the series of light bulbs 48 on opposite sides of and below the openings 34 upwardly at an angle to the openings. Such paths are indicated by arrows 62.

In accordance with the present invention, I have discovered that the angle of the paths 62 of light impinging upon the reaction areas of the slide is critical in order to produce the best compromise between particle illumination of material in the reaction areas of the slide and darkfield effect. If such angle, indicated by the symbol a in FIG. 2, is too large, the darkfield etfect of the illumination device 12 will be lost. For example, if the angle a is 90, there is no darkfield effect at all. If the angle a is too small, the darkfield effect will be maximized but particle illumination for slide agglutination tests will be minimized. In addition, for small angles of a reflection losses of illumination off the bottom 18 of wells 14 in the slide will be substantial. I have determined that the optimum angle range for particle illumination and darkfield effect is between about 30 and 35. In other words, for best results in a slide agglutinationtest the two paths 62 of illumination should impinge upon the flat bottom 18 of each well of the slide from opposite sides at an angle of between about 30 and 35 with respect to the bottom 18 or the horizontal plane as viewed in FIG. 2. Since the surfaces 56 and 60 define the light paths 62, these surfaces must extend at an angle with respect to the horizontal plane corresponding to that required for such paths.

In addition to the angle of illumination, I have found that the manner in which the slide is illuminated also affects the efficiency of the illumination. It is apparent that best illumination will occur when each slide reaction area is uniformly illuminated by all the light from the two light bulbs associated therewith. In one mode, this can be effected by transmitting the light from the two bulbs such that the entire width of the slide reaction area is illuminated by each bulb. In other words, for this mode of illumination the planes in which the inclined surfaces 56 lie would pass through opposite sides of the opening 34. However, I have found that better illumination is obtained by directing the two paths of illumination from the two light bulbs 'so that they pass through only corresponding one-half sections of the opening 34 so that each of the paths of illumination will impinge upon only corresponding one-half sides of the reaction area of the slide. This arrangement is achieved in the device of the present invention by making the planes in which the inclined surfaces 56 lie intersect at the middle of the opening 34 as shown by the phantom lines 64 in FIG. 2.

I have also found that best illumination for slide agglutination tests is achieved by shielding the cylindrical side walls 16 of the wells 14 in the slide so that light from the bulbs 48 will impinge only upon the bottoms 18 of the wells. This is achieved by dimensioning each well 14 so that the outer surface of the cylindrical side wall 16 is in very close proximity to the cylindrical surface 66 of the upper part 24 which forms the opening 34 and so that the bottom 18 of the well does not extend below such surface 66.

While the device of the present invention has been described as employing two sets of bulbs 48 for illuminating the reaction areas of the slide 10, it will be appreciated that, if desired, a single light source or set of bulbs could be used by positioning the same below the surface 58 and using suitable reflectors or light conducting plastics, such as Lucite, to transmit the light from the single source in the paths 62 to the slide. Moreover, an elongated light source could be substituted for the series of bulbs 48 in the channels 40 with out departing from the scope of the invention.

It can be appreciated that by the present invention there is provided a simple and inexpensive device for performing slide agglutination tests in which illumination of the particles and darkfield effect, as well as illumination efficiency, are maximized. While the invention has been described particularly in connection with the performance of slide agglutination tests, obviously the device may be employed for illuminating other objects, such as immunoelectrophoresis plates, for example.

Although only a single embodiment of the invention has been specifically disclosed herein for purposes of illustration, it will be understood that various changes can be made in the form, details, arrangement and proportions of the various parts in such embodiment without departing from the spirit and scope of the invention as defined by the appended claims.

What is claimed is:

l. A device for illuminating a material on a reaction area of a transparent slide comprising:

a casing having at least one opening therein in its upper surface, said casing being adapted to support a slide thereon with said reaction area positioned over said opening;

means in said casing providing a source of illumination;

means in said casing below said opening providing a non-reflective surface disposed in the direction of said opening; and

means for transmitting illumination from said source in two paths extending from opposite sides of and below said opening upwardly at an angle to said opening, said angle being between about 30 and 35 with respect to the horizontal plane.

2. A device as set forth in claim 1 wherein said two paths pass through essentially only corresponding onehalf sections of said opening so that each of said paths of illumination will impinge upon only corresponding one-half sides of said reaction area.

3. A device as set forth in claim 1 wherein: said source of illumination includes two light sources positioned below and at opposite sides of said opening; and said illumination transmitting means includes a pair of inclined channels formed in said casing and intersecting adjacent to said opening, said light sources lying in said channels. 4. A slide agglutination test device combination comprising:

an illumination device and a transparent slide formed with at least one flat-bottomed well providing a reaction area; said illumination device comprising a casing having at least one opening formed in the upper surface thereof; said slide being positioned on said upper surface with said well located over said opening; means in said casing providing a source of illumination; means in said casing below said opening providing a non-reflective surface disposed in the direction of said opening; and means for transmitting illumination from said source in two paths extending from opposite sides of and below said opening upwardly at an angle to the bottom of said slide well, said angle being between about 30 to 35 with respect to said bottom. 5. The combination of claim 4 wherein said two paths pass through essentially only corresponding one-half sections of said slide reaction area.

6. The combination of claim 4 wherein said well includes a shallow generally cylindrical side wall joined to said flat bottom, and said casing shielding said side wall from illumination from said source whereby said illumination impinges upon only the bottom of said well.

7. A slide agglutination test device combination comprising:

an illumination device and a transparent slide formed with at least one flat-bottomed well providing a reaction area;

said illumination device comprising a casing having at least one opening formed in the upper surface thereof; I

said slide being positioned on said upper surface with said well located over said opening;

means in said casing providing a source of illumination;

means in said casing below said opening providing a non-reflective surface disposed in the direction of said opening; and

means for transmitting illumination from said source in two paths extending from opposite sides of and below said opening upwardly at an acute angle to the bottom of said slide well, said two paths passing through essentially only corresponding one-half sides of said slide reaction area. 

1. A device for illuminating a material on a reaction area of a transparent slide comprising: a casing having at least one opening therein in its upper surface, said casing being adapted to support a slide thereon with said reaction area positioned over said opening; means in said casing providing a source of illumination; means in said casing below said opening providing a nonreflective surface disposed in the direction of said opening; and means for transmitting illumination from said source in two paths extending from opposite sides of and below said opening upwardly at an angle to said opening, said angle being between about 30* and 35* with respect to the horizontal plane.
 2. A device as set forth in claim 1 wherein said two paths pass through essentially only corresponding one-half sections of said opening so that each of said paths of illumination will impinge upon only corresponding one-half sides of said reaction area.
 3. A device as set forth in claim 1 wherein: said source of illumination includes two light sources positioned below and at opposite sides of said opening; and said illumination transmitting means includes a pair of inclined channels formed in said casing and intersecting adjacent to said opening, said light sources lying in said channels.
 4. A slide agglutination test device combination comprising: an illumination device and a transparent slide formed with at least one flat-bottomed well providing a reaction area; said illumination device comprising a casing having at least one opening formed in the upper surface thereof; said slide being positioned on said upper surface with said well located over said opening; means in said casing providing a source of illuminatIon; means in said casing below said opening providing a non-reflective surface disposed in the direction of said opening; and means for transmitting illumination from said source in two paths extending from opposite sides of and below said opening upwardly at an angle to the bottom of said slide well, said angle being between about 30* to 35* with respect to said bottom.
 5. The combination of claim 4 wherein said two paths pass through essentially only corresponding one-half sections of said slide reaction area.
 6. The combination of claim 4 wherein said well includes a shallow generally cylindrical side wall joined to said flat bottom, and said casing shielding said side wall from illumination from said source whereby said illumination impinges upon only the bottom of said well.
 7. A slide agglutination test device combination comprising: an illumination device and a transparent slide formed with at least one flat-bottomed well providing a reaction area; said illumination device comprising a casing having at least one opening formed in the upper surface thereof; said slide being positioned on said upper surface with said well located over said opening; means in said casing providing a source of illumination; means in said casing below said opening providing a non-reflective surface disposed in the direction of said opening; and means for transmitting illumination from said source in two paths extending from opposite sides of and below said opening upwardly at an acute angle to the bottom of said slide well, said two paths passing through essentially only corresponding one-half sides of said slide reaction area. 